The threads of pipe, such as pipe used in transfer of gas or oil, are, during loading, transport, unloading and storage prior to use, often subjected to impacts and collection of dirt, water and the like which adversely affect the threads. Often, when the threads are damaged, the complete pipe section must be replaced. While the external threads of a pipe are more susceptible to such adverse effects, the internally threaded end of a pipe is also subject to damage. For example, in transferring pipe, cranes are used which use hooks inserted into the pipe, which hooks can damage the thread. Of course, the collection of dust, water and other undesirable materials within the internal threads is always a problem in storage, so that the complete and constant protection of the threads is greatly desired. Couplings for externally threaded pipe are also faced with these problems where the internal threads of the couplings are subject to damage or defacing.